Acute respiratory distress syndrome (ARDS) in adults and RDS in premature newborns cause significant morbidity and mortality despite the best available hospital care. The long term goals of this research are to determine the molecular mechanisms through which cytokines mediate surfactant dysfunction and pulmonary failure in respiratory distress syndrome (RDS). The pro-inflammatory cytokine, tumor necrosis factor alpha (TNF), has a central role in the pathogenesis of ARDS associated with sepsis. TNF levels are increased and surfactant proteins are decreased in the bronchoalveolar lavage fluid of ARDS patients. TNF inhibits transcription of surfactant protein-c (SP-C) in a mouse model of ARDS and in a cell culture system. Previous work from this laboratory identified the critical roles of the nuclear transcription factors TTF-1 and NFI in regulation of SP-C transcription. Recently, TNF was shown to inhibit transcription of another NFI dependent promoter in vitro. This proposal will focus on the role of the nuclear factor in (NFI) transcription factor family in the regulation of surfactant protein-C transcription to determine the molecular mechanisms regulating Type II cell differentiation and response to TNF. The overall hypothesis to be tested is that NFI family member interactions regulates SP-C transcription. This project will use biochemical and genetic models in vitro and in vivo in NFI-A (-/-) mice to determine the contribution of NFI isoform repertoire to regulation of SP-C transcription in Type II cells. Aim 1] will determine the functional role of NFI isoforms in regulation of SP-C promoter activity in Type II cells and in response to TNF in vitro. Aim 2] will determine whether perturbation of the NFI repertoire in NFI-A (-/-) mice affects SP-C expression during lung development. Aim 3] will define which tumor necrosis factor receptor 1 (TNFR1/CD120a) mediated signal transduction cascade(s) triggers inhibition of SP-C transcription. This proposal will define the role of NFI family members in the regulation of SP-C transcription in Type II cells. Defining the factors and signal transduction pathways regulating surfactant protein expression during development and causing surfactant dysfunction in response to TNF, a primary mediator of acute lung injury, will provide a basis to design more specific and effective therapies for ARDS.